On October 20, NOAA released their Seasonal Outlook. Last week, JAMSTEC, which is a Japanese Research Institute, issued their Outlook based on their October 1 forecast for ENSO. We compare the JAMSTEC temperature and precipitation forecast maps which are for the World with the NOAA temperature and precipitation forecast maps that cover only CONUS and Alaska. We do this primarily for educational purposes. Remember: these are forecasts not guarantees. But the differences between the NOAA and JAMSTEC forecasts are significant and mostly related to the differing perspectives on the strength and duration of this Cool ENSO Event.
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NOAA Updated Seasonal Outlook
NOAA issued their updated Seasonal Outlook on the third Thursday of the month i.e. October 20, 2016 as is their normal schedule. Let's take a look.
We have nothing to compare these maps with as NOAA does not in their Update provide a forecast for two months out. Thus I do not have November maps from the September 15 NOAA Report to compare against. And October is not over so we can not really compare against last month. It is probably best to just try to understand what NOAA is trying to convey about November which can be summarized as warmer than climatology pretty much everywhere except for the Northwest and Florida which are EC and when it comes to precipitation, it is a wet Northwest and dry Southern Tier with EC elsewhere. Alaska is mostly warm and EC relative to precipitation except along the North Shore.
Now we consider the three-month Outlook.
Notice that the three-month periods are abbreviated e.g. November/December/January is shown as NDJ. You will see such abbreviations often in this report.
Prior Temperature Outlook for NDJ 2016
New Temperature Outlook for NDJ 2016
It is fairly similar with the East Coast being added to the Warm Anomaly the extreme Northwest being added to the EC category i.e. Equal Chances of being more or less than normal.
Prior Precipitation Outlook for NDJ 2016
New Precipitation Outlook for NDJ 2016
The major change is the addition of the small Great Lakes wet anomaly. This may be related to a forecast of an Negative AO which allows the Polar Vortex to extend into CONUS.
Now let us focus on the long-term situation and compare the new set of maps with the maps issued on September 15, 2016.
Prior 14 Month Temperature Outlook: NDJ 2016 - OND 2017
New 14 Month Temperature Outlook: DJF 2016/2017 - NDJ 2017/2018
To compare maps from one release to another one needs to remember that the new release drops one three-month period and adds a later one. So to make the comparisons one has to shift the new maps to the right one position and that makes the map on the right drop down to become the left-most map in the next level. I do not have a computer software tool for doing that for you so you have to do it mentally. When I do the comparison, I print the two sets of maps and put them side by side and number the same three-month maps 1, 2, 3,.....,11 in both sets of maps to make it easier for me to easily compare the same three-month period in the new with the previous forecast. One uses the same procedure to compare the precipitation maps. Based on this procedure, I conclude that:
The major change is that starting in JFM and repeating in FMA, the North-Central Cool Anomaly extends to the West Coast. That is pretty much a reversal of the change made last month to the forecast made the month before and simply represents the ever changing attitude of NOAA towards this ENSO Cool Event. When they think it will be weaker, the Northern Tier cool anomaly shrinks. When they think it will be stronger, the Northern Tier cool anomaly expands. Another change relates to the tail end of the cool anomaly and now starting in MJJ 2017 the West Coast Warm Anomaly extends to the Canadian Border. So really, the only major change in the NOAA Temperature Outlook issued on October 20 is to the Northwest with it being estimated by NOAA to being significantly impacted a month earlier by the Cool Event and five months later ceasing to be significantly impacted.
Prior 14 Month Precipitation Outlook: NDJ 2016 - OND 2017
New 14 Month Precipitation Outlook: DJF 2016/2017 - NDJ 2017/2018
The main change is that in MAM 2017, the Southern Tier dry anomaly shrinks to basically Arizona/New Mexico and West Texas with points east which last month had been indicated to be dry are now forecast to be EC. NDJ (2017/2018) is added as this forecast goes for one additional month as compared to the prior outlook and it shows the extreme Southeast to have a dry anomaly. It is pretty interesting that they are projecting a dry anomaly more than a year in advance.
If you want larger versions of each map (temperature and precipitation) you can find them here. And each of those maps can be clicked on to further enlarge them.
Below are excerpts (significantly reorganized and with a lot of the redundancy removed) from the Discussion released by NOAA on October 20, 2016. Headings that are "Initial Cap" only rather than all caps were added by the Author of this Update Report for clarity. Also we have organized the sequence of the sections of NOAA Discussion to first present the Atmospheric Conditions and then the Current Month, the Three or Four-month period, and finally the remainder of the 15 Month Forecast. We think that sequence with the three- to four-month period broken out separately, makes the discussion more useful for more readers.
CURRENT ATMOSPHERIC AND OCEANIC CONDITIONS
IN THE TROPICAL PACIFIC, BOTH OCEANIC AND ATMOSPHERIC OBSERVATIONAL INDICATORS (ON AVERAGE) HAVE TRENDED TOWARD VALUES AND PATTERNS THAT ARE CONSISTENT WITH LA NINA CONDITIONS OVER THE PAST FEW WEEKS.
SEA SURFACE TEMPERATURES (SSTS) ALONG THE EQUATOR IN THE PACIFIC BASIN REMAIN BELOW AVERAGE FROM 170W TO 100W, WHILE SSTS ARE ABOVE AVERAGE ACROSS THE FAR WESTERN PACIFIC AND IN A HORSESHOE PATTERN NORTH AND SOUTH OF THE AREA OF COOLER THAN NORMAL SSTS ALONG THE EQUATOR. IN THE NINO3.4 REGION, THE MOST RECENT WEEKLY ANOMALY VALUE IS -0.6 DEGREES C WHILE THE MOST RECENT THREE-MONTH AVERAGE NINO3.4 SST ANOMALY IS -0.5 DEGREES C FOR THE JAS SEASON. A RESERVOIR OF ANOMALOUSLY COOL SUBSURFACE WATERS CONTINUES AT DEPTH AND EXTENDS TO MORE THAN 150 METERS BELOW THE SURFACE, WITH THE LARGEST NEGATIVE ANOMALIES OF 2-4 DEGREES C BELOW AVERAGE FROM 50-150 METERS BETWEEN 140W-170W.
ENHANCED CONVECTION HAS BECOME MORE ORGANIZED ACROSS THE MARITIME CONTINENT, THE FAR WESTERN PACIFIC AND NORTHERN AUSTRALIA IN RECENT WEEKS WHILE SUPPRESSED CONVECTION ACROSS THE CENTRAL PACIFIC HAS CONTINUED. THIS DIPOLE PATTERN IN ANOMALOUS CONVECTION HAS BECOME MORE ROBUST OVER THE LAST FEW WEEKS. MOREOVER, TRADE WINDS OVER THE PACIFIC BASIN HAVE INCREASED WITH EASTERLY ANOMALIES NOW MORE PREVALENT IN THIS AREA IN ADDITION TO PERSISTENT WESTERLY WIND ANOMALIES OVER THE PAST MONTH CENTERED BETWEEN 100-120 E. UPPER-LEVEL WINDS ARE ANOMALOUSLY WESTERLY OVER THE EQUATORIAL PACIFIC FROM THE DATE LINE EASTWARD.
SSTS IN THE NORTH PACIFIC AND ALONG THE COAST OF ALASKA REMAIN ABOVE AVERAGE, ALTHOUGH THESE DEPARTURES FROM NORMAL IN AREAS OF THE NORTH PACIFIC HAVE DECREASED SOME OVER THE PAST MONTH. POSITIVE SST ANOMALIES PERSIST IN THE WESTERN ATLANTIC NEAR THE U.S. EAST COAST, AND THE GULF OF MEXICO.
PROGNOSTIC DISCUSSION OF SST FORECASTS
THE CPC SST CONSOLIDATION FORECAST, WHICH INCLUDES THREE STATISTICAL FORECASTS ALONG WITH THE CFS, PREDICTS A WEAK LA NINA [Editor's note: I believe it would be more correct to have said La Nina conditions rather than La Nina i.e. they should observe their own criteria]. FROM NDJ 2016-2017 THROUGH JFM 2017 WITH ENSO-NEUTRAL CONDITIONS FAVORED THEREAFTER. THE STATISTICAL GUIDANCE IN THIS FRAMEWORK IS SLIGHTLY WARMER THAN THE CFS. THE NORTH AMERICAN MULTI MODEL ENSEMBLE (NMME) ENSEMBLE MEAN FORECAST FOR THE NINO3.4 SST ANOMALY IS SIMILAR TO THE ABOVE WITH A FORECAST NEAR -0.5 DEGREES C THROUGH DECEMBER 2016 BEFORE TRENDING TO NEAR ZERO BY MARCH 2017. BASED ON THE LATEST OBSERVATIONAL AND MODEL FORECAST INDICATORS, THE OFFICIAL CPC/IRI ENSO OUTLOOK FAVORS LA NINA CONDITIONS THROUGH THE DJF SEASON WITH PROBABILITIES RANGING FROM NEAR 70% DURING NDJ 2016-2017 TO NEAR 55% BY DJF 2016-2017. [Editor's Note: Later in this report we show the IRI/CPC ENSO forecast which was also issued on October 20 and we believe that the change in forecast by IRI/CPC is not reflected in the NOAA Seasonal Outlook Update Issued on October 20 and that is a big problem.]
30-DAY OUTLOOK DISCUSSION FOR NOVEMBER 2016
DURING THE PAST MONTH, CONDITIONS OVER THE TROPICAL PACIFIC HAVE BECOME MORE CONSISTENT WITH A DEVELOPING LA NINA EVENT. COUPLED WITH THE CONSENSUS AMONG VARIOUS DYNAMICAL AND STATISTICAL TOOLS, ODDS ARE NOW TILTED IN FAVOR OF LA NINA OVER THE COMING MONTHS. AS A RESULT, STATISTICAL GUIDANCE THAT USES ENSO AS A PREDICTOR IS STRONGLY CONSIDERED FOR THIS OUTLOOK. [Editor's note: One wonders if NOAA is differentiating between a borderline La Nina event and the average La Nina event. It is difficult to tell but they seem to possibly have gone overboard.]
MJO INDICES (CPC VELOCITY POTENTIAL AND RMM) INDICATE NO APPRECIABLE, COHERENT MJO ACTIVITY DURING THE PAST MONTH AND FORECASTS DO NOT DEPICT CLEAR, LONG TERM STRENGTHENING AT THE CURRENT TIME. THEREFORE, THE MJO DOES NOT INFLUENCE THE NOVEMBER OUTLOOK AT PRESENT.
THE NOVEMBER 2016 TEMPERATURE AND PRECIPITATION OUTLOOKS ARE PRIMARILY BASED ON CALIBRATED DYNAMICAL GUIDANCE, ALONG WITH STATISTICAL GUIDANCE THAT EMPHASIZES ENSO AND LONG-TERM TRENDS. COASTAL SST ANOMALIES ALSO PLAYED A SMALL ROLE IN THE OUTLOOK, PRIMARILY FOR AREAS NEAR ALASKA.
THE NOVEMBER TEMPERATURE OUTLOOK FAVORS ABOVE-NORMAL TEMPERATURES FOR MOST OF THE FORECAST DOMAIN. THE ENSO SIGNAL AND LONG-TERM TRENDS TOGETHER PLACE THE HIGHEST PROBABILITIES FOR ABOVE-NORMAL TEMPERATURES OVER THE SOUTHWESTERN AND SOUTH-CENTRAL U.S. EXTENDING NORTHEASTWARD THROUGH THE UPPER MIDWEST, GREAT LAKES, AND NORTHEAST. LONG-TERM TRENDS ARE STRONG OVER ALASKA. EQUAL-CHANCES OF BELOW-, ABOVE-, AND NEAR-NORMAL TEMPERATURES IS INDICATED OVER A SMALL PORTION OF INTERIOR ALASKA, THE PACIFIC NORTHWEST, AND THE FAR SOUTHEASTERN PORTION OF THE CONUS. THE CALIBRATED GUIDANCE FROM THE NMME, INITIALIZED EARLY THIS MONTH, STRONGLY SUPPORTS THIS PATTERN. MORE RECENTLY INITIALIZED GUIDANCE FROM THE CFS FAVORS A VERY WARM SOLUTION ACROSS MOST OF NORTH AMERICA.
INTERESTINGLY, THIS PATTERN IS GENERALLY AN EXTENSION OF THE CURRENT WEEK-2 FORECAST, SUGGESTING A FAIRLY PERSISTENT PATTERN. RECENT WEEK 3/4 GUIDANCE GENERALLY SUPPORTS THE CONTINUATION OF THIS PATTERN THROUGH THE FIRST PART OF THE MONTH, THOUGH RECENT RUNS OF THE CFS AND THE ECMWF ENSEMBLES SUGGEST THAT SOME PATTERN CHANGE MAY EVOLVE DURING THE MIDDLE PORTION OF THE MONTH. INDEED, THEREIN LIES THE KEY UNCERTAINTY IN THE TEMPERATURE FORECAST. THE RECENT PATTERN HAS BEEN FAIRLY PERSISTENT OVER NORTH AMERICA, BUT AS THE SEASONAL CYCLE UNFOLDS, THE PATTERN IS EXPECTED TO EVOLVE ON LOW-FREQUENCY TIMESCALES TOWARD SOMETHING MORE AKIN TO THE LA NINA EXTRATROPICAL RESPONSE, WITH MORE SEASONABLE TEMPERATURES AND EVEN BELOW-NORMAL TEMPERATURES ACROSS PARTS OF THE NORTHERN CONUS. IN REALITY THIS CHANGE (IF IT HAPPENS) WILL OCCUR ACROSS A SERIES OF SYNOPTIC EVENTS, THE TIMING OF WHICH IS DIFFICULT TO CAPTURE IN A 0.5-MONTH LEAD MONTHLY FORECAST.
THE PRECIPITATION OUTLOOK IS BASED LARGELY ON CORRELATIONS WITH ENSO, WHICH EVEN IN NOVEMBER BEGIN TO SHOW A FAIRLY CANONICAL LA NINA PATTERN. ABOVE-MEDIAN PRECIPITATION IS FAVORED OVER THE NORTHERN ROCKIES EXTENDING TO THE PACIFIC NORTHWEST, WHILE BELOW-MEDIAN PRECIPITATION IS FAVORED ACROSS MUCH OF THE SOUTHERN TIER OF THE CONUS. THIS PATTERN IS ALSO STRONGLY SUPPORTED BY THE CALIBRATED NMME GUIDANCE AND RECENT RUNS OF THE CFS. DURING THE LAST WEEK OF OCTOBER, ABOVE-MEDIAN PRECIPITATION IS FAVORED OVER MUCH OF THE WESTERN CONUS. HOWEVER, THERE IS LITTLE REASON TO BELIEVE THAT THIS SIGNAL WILL PERSIST OVER THE SOUTHWEST AND SOUTH-CENTRAL U.S. INTO NOVEMBER GIVEN THE LOW-FREQUENCY BACKGROUND STATE. AS WITH THE TEMPERATURE OUTLOOK, PROBABILITIES ARE MODEST ACROSS THE FORECAST DOMAIN GIVEN THE AFOREMENTIONED UNCERTAINTY.
Three Month Forecast: November - December 2016 and January 2017
THE NDJ 2016-2017 TEMPERATURE OUTLOOK INDICATES INCREASED PROBABILITIES OF ABOVE-NORMAL TEMPERATURES FOR MOST OF THE CONTIGUOUS U.S. AND ALASKA, WITH THE EXCEPTIONS BEING AREAS OF EAST-CENTRAL ALASKA AND A REGION ALONG THE NORTHERN TIER OF THE U.S. THAT STRETCHES FROM PARTS OF THE PACIFIC NORTHWEST EASTWARD THROUGH THE GREAT LAKES. THE EXCEPTIONS ARE WHERE THERE IS MORE UNCERTAINTY IN THE OUTLOOK RELATIVE TO THE REST OF THE FORECAST DOMAIN. THE GREATEST LIKELIHOOD FOR ABOVE-NORMAL TEMPERATURES IS FOR AREAS OF THE U.S. SOUTHWEST WHERE LA NINA CONSIDERATIONS, SHORT-TERM CLIMATE MODEL OUTPUT AND HISTORICAL TRENDS FAVOR HIGHER PROBABILITIES.
THERE IS INCREASED UNCERTAINTY, PREDOMINATELY DURING DECEMBER AND JANUARY FOR PARTS OF THE NORTHERN PACIFIC NORTHWEST, NORTHERN GREAT PLAINS AND GREAT LAKES REGIONS AND FORECAST TOOLS ARE MORE MIXED IN THESE AREAS SO EC IS INDICATED. FOR ALASKA, ABOVE NORMAL TEMPERATURES ARE FAVORED FOR COASTAL AREAS AND IS SUPPORTED BY ABOVE AVERAGE NEAR-COASTAL SSTS, TRENDS IN SEA ICE COVERAGE AND DYNAMICAL MODEL GUIDANCE.
THE NDJ 2016-2017 PRECIPITATION OUTLOOK INDICATES INCREASED PROBABILITIES OF ABOVE-MEDIAN PRECIPITATION FOR PARTS OF THE PACIFIC NORTHWEST, NORTHERN ROCKIES, NORTHERN GREAT PLAINS, AND GREAT LAKES AS WELL AS AREAS IN WESTERN AND NORTHERN ALASKA. BELOW-MEDIAN PRECIPITATION IS FAVORED FOR MUCH OF THE SOUTHERN TIER OF THE CONTIGUOUS U.S. WITH THE GREATEST PROBABILITIES ALIGNED FROM EASTERN TEXAS TO THE FLORIDA PANHANDLE. THE OUTLOOK IS BASED ON A NUMBER OF FACTORS INCLUDING LA NINA CONSIDERATIONS AND SHORT TERM CLIMATE MODEL OUTPUT.
IN ADDITION, BELOW-MEDIAN PRECIPITATION IS INTRODUCED DURING DJF 2016-2017 AND JFM 2017 FOR COASTAL SOUTH-CENTRAL ALASKA SUPPORTED BY LA NINA CONSIDERATIONS AND DYNAMICAL MODEL GUIDANCE.
PROGNOSTIC DISCUSSION OF OUTLOOKS - beyond NDJ (2016/2017). I have moved the NDJ (2016/2017) part of the discussion above to reduce redundancy and be more useful to the reader)
INTO AND THROUGH THE WINTER, BELOW NORMAL TEMPERATURES ARE INTRODUCED FIRST FOR PORTIONS OF THE NORTHERN GREAT PLAINS AND WESTERN GREAT LAKES AND LATER EXPANDED AND SHIFTED WESTWARD TO INCLUDE NORTHERN AREAS OF THE ROCKIES AND PACIFIC NORTHWEST BY FMA 2017. THE HIGHLIGHTED AREAS FOR THIS EVOLUTION ARE WHERE THE GREATEST AGREEMENT AND CONSISTENCY IN FORECAST TOOLS WAS INDICATED. CONSIDERATIONS OF LA NINA (REGRESSIONS ANCHORED TO THE CPC SST CONSOLIDATION AND TRENDS) OVER THE COURSE OF THIS PERIOD AND STATISTICAL GUIDANCE FROM THE CCA AND LATER CA WERE UTILIZED FOR THE OUTLOOK. ABOVE NORMAL TEMPERATURES REMAIN FAVORED ACROSS THE SOUTHERN TIER OF THE CONTIGUOUS U.S. WITH THE GREATEST PROBABILITIES OVER THE SOUTHWEST. ODDS FOR ABOVE-NORMAL TEMPERATURES DECREASE ACROSS PARTS OF THE INTERIOR WEST OVER THIS PERIOD, CONSISTENT WITH DYNAMICAL MODEL GUIDANCE.
THE OUTLOOKS FROM MAM 2017 AND BEYOND PRIMARILY REFLECT INPUT FROM THE CPC CON, TRENDS AND THE CA BASED ON GLOBAL SST AND SUCH FAVOR ABOVE NORMAL TEMPERATURES FOR MUCH OF THE CONUS AND ALASKA. DYNAMICAL MODEL GUIDANCE FROM THE NMME WAS CONSIDERED FOR THE MAM 2017 OUTLOOK AND TRENDS IN SEA ICE EXTENT INCREASE PROBABILITIES FOR ABOVE-NORMAL TEMPERATURES FOR THE NORTH SLOPE OF ALASKA DURING SON AND OND 2017.
THE PRECIPITATION OUTLOOK REMAINS SIMILAR, TO THE FIRST ORDER, THROUGH FMA 2017 WITH A FAVORED ACTIVE NORTHERN STREAM AND WETTER THAN AVERAGE CONDITIONS MOST LIKELY IN THE AFOREMENTIONED AREAS. COVERAGE FOR ABOVE-MEDIAN PRECIPITATION IS SLIGHTLY INCREASED IN DJF 2016-17 AND JFM 2017 IN SOME AREAS AS ANY LA NINA INFLUENCE LIKELY MAY BE MORE PRONOUNCED IN THESE SEASONS AND SIGNALS FROM THE DYNAMICAL MODEL GUIDANCE ARE SLIGHTLY STRONGER. BELOW MEDIAN PRECIPITATION REMAINS FAVORED FOR THE SOUTHERN TIER DURING THESE SEASONS WITH THE LOWEST COVERAGE AND PROBABILITIES INDICATED IN FMA 2017.
POSITIVE PRECIPITATION TRENDS CONTRIBUTE TO THE OUTLOOK ACROSS SOME AREAS OF THE NORTHERN PLAINS AND GREAT LAKES BEGINNING IN FMA 2017 AND THIS CONTINUES THROUGH MJJ 2017. A POSITIVE TREND SIGNAL IS ALSO EVIDENT AND DEPICTED ACROSS THE NORTHEAST CONUS FROM JJA 2017 THROUGH SON 2017. DRIER THAN AVERAGE CONDITIONS ARE FAVORED FOR MAM AND AMJ 2017 ACROSS THE SOUTHWEST BASED ON NEGATIVE HISTORICAL PRECIPITATION TRENDS.
It would be helpful if NOAA divided "Decadal Trends" in the impact of the AMO and PDO and the impact of the secular trend of Global Warming. As it is, the reader is left with trying to figure out what NOAA is saying when they discuss Decadal Trends.
Here is the latest NOAA forecast of Nino 3.4 temperature anomalies. This graphic does auto-update daily but changes slowly. You can see the "blue" newer model runs and the "red" older model runs. The Oceanic Niño Index (ONI) which is the three-month rolling average of the Nino 3.4 values is NOAA's primary indicator for monitoring El Niño and La Niña. The secondary indicator is the Southern Oscillation Index (SOI) which compares the air pressure in Tahiti with the air pressure in Darwin Australia. It is a complicated formula and is intended to assess the response of the atmosphere to the changes in the pattern of warm and cool anomalies measured by the Nino 3.4 Index. It confirms rather than predicts the phases of ENSO.
At this point in time, the forecast is that Nino 3.4 will rise (a bit less La Nina-ish) in November and then decline (a bit more La Nina-ish) to -0.8 or so during NDJ and DJF. Those are La Nina values but most likely all the criteria for having a La Nina declared (in particular a sufficient duration of the ONI being -0.5 or lower) will not have been met which is why so far I am describing this event as La Nina-ish. That could change. Sometimes NOAA gets a bit carried away and violates their own criteria which they did in 2015 and had to recant from having declared the 2014/2015 an El Nino. But one can make an argument that even though the criteria were not fully met, we really had a 2014/2016 El Nino. In reality, fully meeting the criteria or just missing may have little impact on the weather that occurs. .
Here is their latest output: Click the link above for updates which are issued on approximately the second and third Thursdays of each month.
And part of their discussion:
What is the outlook for the ENSO status going forward? The most recent official diagnosis and outlook was issued one week ago in the NOAA/Climate Prediction Center ENSO Diagnostic Discussion, produced jointly by CPC and IRI; it carries a La Niña watch and called for a roughly 70% likelihood of La Niña conditions during fall (already underway) 55% for La Niña in winter 2016-17. The latest set of model ENSO predictions, from mid-October, now available in the IRI/CPC ENSO prediction plume, is discussed below. Currently, the Nino3.4 SST anomalies are at the level of weak La Niña. Subsurface temperature anomalies across the eastern equatorial Pacific continue to be somewhat below average. Slightly enhanced easterly trade winds have been observed in the west-central tropical Pacific, suggestive of La Niña, but not compelling so far. The pattern of sea level pressure (e.g., the SOI), the upper level winds, and the pattern of tropical convection have been more suggestive of La Niña, so that overall, the atmosphere and ocean do appear La Niña-like in mid-October. But the hitch is that these conditions are instantaneous (or, just a mean over one week), and the question of endurance causes some to doubt that the ocean-atmosphere coupling is really in motion. The negative subsurface heat content anomaly may support the extension of the enhanced trades farther east in the tropical Pacific, which would present a more compelling picture of a La Niña. When and if these develop, the SST could remain in the weak La Niña category, or even strengthen somewhat, during the rest of 2016 and into the early part of 2017. The collection of the latest model predictions suggest that this scenario is about 55-60% likely.
As of mid-October, 62% of the dynamical or statistical models predicts La Niña conditions for the initial Oct-Dec 2016 season, while 38% predict neutral ENSO. At lead times of 3 or more months into the future, statistical and dynamical models that incorporate information about the ocean’s observed subsurface thermal structure generally exhibit higher predictive skill than those that do not. For the Jan-Mar 2017 season, among models that do use subsurface temperature information, 38% predicts La Niña conditions and 62% predicts ENSO-neutral conditions. For all model types, the probabilities for La Niña are over 60% for Oct-Dec 2016 and Nov-Jan 2017, 46% for Dec-Feb 2016-17, then drop to near 30% for Jan-Mar and drop further to about 10-20% from Feb-Apr to Jun-Aug 2017. The probability for neutral conditions is at least 50% beginning in Dec-Feb 2016-17, and rises to at least 80% from Feb-Apr to Apr-Jun 2017, then drops somewhat for later seasons. Probabilities for El Niño are near zero until Mar-May 2017, when they rise to 5%, and then up to around 20% for May-Jul and Jun-Aug.
And here is the recently released JAMSTEC Nino 3.4 Forecast. It does not auto-update.
Based on the Nino 3.4 projection, JAMSTEC is saying "no" to La Nina...NOAA says "Maybe but if so marginal".
Here is the Nino 3.4 report from the Australian BOM. It will update automatically on Tuesday morning or late Monday night.
Sometimes it is useful to compare the present month outlook to the three-month outlook
One can mentally subtract the November Outlook from the three-month Outlook and create the Outlook for the last two months in the three-month period namely December 2016 and January 2017. When I do that, I deduce that:
With respect to temperature, The three month forecast has a larger EC area across the Northern Tier. This suggests that December and January may have to be a bit cool for the three-month average to work out. The precipitation relates mainly to the small Great Lakes anomaly shown for the three-month period but not for November. This suggests the probabilities for that area to be wet in December and January might be a bit higher than shown on the three-month map. Also the dry anomaly across the Southern Tier is larger in November than in the three-month forecast map so where the November anomaly is larger, it is possible that those ares will need to be a bit wet in December or January for the three-month average to work out. .
The whole idea is that a three-month average set of probabilities for anomalies is the sum of that information for three months. If you have the first month differing in places from the three-month average you can calculate what a map of the second and third month would look like.for the sum of the two maps ( November and December/January) to equal the published three-month map.
Now the Comparison of the NOAA and JAMSTEC Forecasts. I am only discussing the differences for CONUS since NOAA does not cover the World in this set of forecasts. But the JAMSTEC World forecast is here for you to see:.
For JAMSTEC all of CONUS is warm. NOAA shows a cool anomaly across North Central CONUS.
Here I just focus on Europe and CONUS
Kind of Dry! For the most part. Remember this is December 2016 through February 2017
Notice the different pattern between NOAA and JAMSTEC. NOAA is classical La Nina. They may have it correct but they also may not.
Here is one more forecast but it is not exactly the same months.
This is the precipitation forecast from Queensland Australia.
It is kind of amazing that you can make a worldwide forecast based on just one parameter the SOI and changes in the SOI. Notice that the rising SOI triggers a lot of wet around the World. Look for low grain prices. For CONUS it is a lot wetter than either NOAA or JAMSTEC and with a different pattern. And the SOI may have stopped rising. .
Again JAMSTEC is all warm for CONUS with NOAA having the Northern Tier be EC. JAMSTEC even predicts a cool Northeast.
JAMSTEC has more of a East/West divide with NOAA having a north/south La Nina divide.
Strange! JAMSTEC finally goes all in with a cool Northern Tier and warm Southern Tier but NOAA is all warm with a small EC area. Again it has to do probably with differing ideas of how the ENSO Cool Event will play out.
Now JAMSTEC has the North/South divide and NOAA has just two anomalies, one in the Northeast and one in the Northwest. JAMSTEC seems to be forecasting a weak Southwest Monsoon.
Most of the differences can be explained by the differing forecasts for ENSO with NOAA being far more all in on the La Nina scenario than JAMSTEC
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